The invention concerns a method for packaging product portions in a wrapper, wherein at least two webs of packaging material are aligned essentially parallel, with the longitudinal edges facing each other overlapping, and are each transported towards an upwardly open folding shaft, the webs are severed transverse to the overlapping longitudinal edges, creating substantially flat blanks of the wrappers, and the blanks are folded into the folding shaft by means of a folding stamp inserted into the folding shaft, creating an upwardly open wrapper, whereupon the product portion is placed on the upwardly open wrappers and the upwardly protruding sections of the wrappers are turned inward. The invention further concerns a device suitable in particular for using such a method for packaging product portions in a wrapper, having at least two parallel, upwardly open folding shafts, to each of which a folding stamp, insertable into the respective folding shafts, is allocated, with an adjusting unit structured and disposed to align at least two webs of a packaging material substantially parallel, with the two longitudinal edges facing each other overlapping, with a cutting device acting transverse to the longitudinal edges of the webs, and with a transport device structured and disposed to transfer the web blanks created by means of the cutting device to the folding shafts.
Methods and devices of the above-mentioned kind are known and widely used in particular for portioned packaging of more or less paste-like foods such as butter, margarine, paste-like fats, processed and fresh cheese, chocolate, soup pastes, and the like. The process usually involves initially creating flat blanks from a running web of packaging material. The blanks then run over two parallel folding shafts. A folding stamp pulls the blank through the folding shaft, wherein the folding stamp and/or the folding shaft are equipped with appropriate guiding devices for creating the folds and for overlapping the sections of the blank which are to be placed on top of each other. This method creates a wrapper which is only upwardly open, which can subsequently be placed in a cell, for example, where the wrapper is then filled with the product portion. Finally, the upwardly protruding lateral parts of the wrapper are folded inward onto the open side of the product. Methods and devices for packaging paste-like products in such a way are known, for example, from DE 101 00 085 A1 and DE 103 30 725 A1.
It is usually desirable to dispose the folding shafts as closely together as possible. This is for reasons of space to ensure that the device is as compact as possible and that routes of transport of the packaging material and/or of the wrapper pre-folded in the folding shafts, which are needed for the very short cycle times and therefore the efficiency of modern packaging devices, are short. Furthermore, the folding shafts are often disposed in the peripheral area of a carousel, which forwards the wrappers which have been pre-folded in the folding shafts and can be placed in cell-like cavities, for example, to downstream stations which are also disposed in the peripheral area of the carousel, such as a filling station, a plying station to fold those sections of the wrapper that protrude upwardly over the portioned product, a removal station for the finished packages, etc.
For this reason, it is known to feed a broad web of packaging material to the two folding shafts in such a way that the web of packaging material extends across both folding shafts, whereupon it is severed in a transverse manner, creating a wide blank. Before it is folded into the folding shafts, the central section of this blank from the web of packaging material, which is located between the folding shafts, is lifted by means of folding stamps which are inserted into the folding shafts from above so that its two outer longitudinal edges are pulled inside to place the folding shafts as closely together as possible. Once the blank has reached its desired position relative to the folding shafts by pulling its edges inside accordingly as a result of the central lifting of the blank, the blank is severed lengthwise centrally, creating the two wrappers to be folded, which is done, for example, by means of a blade disposed at the lifting device. The wrappers are then folded into the folding shafts by means of the folding stamps, and the pre-folded, upwardly open wrappers are supplied to further processing stations (filling etc.). It is particularly unfavorable that the packaging material cannot always be aligned accurately over the two folding stamps, in particular when cycle times are very high, and that aligning the wide blank of packaging material by lifting it centrally also causes relatively high stress on the material, so that the method is not suitable for all packaging materials, in particular those with a relatively low resistance to tearing.
It is further known to align two webs of packaging material relative to each other in such a way that the longitudinal edges facing each other overlap. This is achieved by central, lengthwise severing of a wide web of packaging material to form two parallel webs and by guiding one of the two webs over traversing rollers directly upstream of the folding shafts to move it towards the other web parallel to it. The webs are then severed in transverse manner, creating blanks for the wrappers, and the blanks are folded into the folding shafts by means of the folding stamps. Furthermore, guide bars are disposed which support the longitudinal edges of the webs and/or blanks opposite to each other to ensure exact alignment of the two webs relative to each other. In this case, primarily the complex structure of the device required due to the necessary traversing roller is unfavorable, as is the fact that the device can in particular not, or only with difficulty, be adjusted to different formats of packaging material.
Against this background, the invention is based on the task of further developing a method and a device of the above-mentioned kind in a simple and cost-effective manner so as to avoid the above-mentioned disadvantages to the greatest possible extent.